This paper presents research focused on studying the behaviour and properties of wood-cement composites under changes in relative humidity. The behaviour and the resulting changes in properties with variations in air (relative) humidity are significantly influenced by the chips contained. The chips are mineralised or stabilised during the manufacturing process. The by-product (particle mixture) from the production of cement-bonded particleboards, which was used to modify the composition of the composites, already contained mineralised spruce chips (i.e. stabilised properties and structure). The goal of the research was to study the sorption mechanisms in terms of dimensional and volumetric changes, including the assessment of the composite materials' performance properties (density, strength characteristics and modulus of elasticity). Thus, the influence of spruce chips stabilization in terms of different matrix compositions of the composites was also partially, indirectly analysed. Three variants of composites were tested - 2 types of reference (based on Portland and blended cement); 1 type with modification of the binder and filler with particle mixture produced during the production of cement particleboards (4% cement substitution, 4% substitution of primary chips). For the determination of each point of the sorption curves, the test bodies were always exposed to a given moisture content for a period of time to allow their mass to settle. The sorption isotherms indicate the different behaviour of the plates during the increase and decrease of the ambient air humidity. Differences were also observed in the case of hysteresis. The modification of the composition of the mixture for the production of cement-bonded particleboards has an effect, among other things, on the stabilisation of the spruce chips. The changes in physical and mechanical properties are practically negligible in terms of the practical use of the boards with modified composition.

Contemporary architecture often works with glass facades, roofs or even glass columns and beams. The problematic part of a glass structure design is usually a connection between the glass elements and the rest of structure. In order to achieve as much transparency as possible, various mechanical point fixing systems, adhesive connections and their combinations were developed. Although being widely used, the design procedure is mostly based on experiments. There is ongoing research at the Czech Technical University in Prague focusing on characteristics of an embedded laminated connection under various types of loads. Within the initial phase of experiments, small scale specimens consisting of different glass and foil types were tested. The experiments revealed the tensile, eccentric shear and compressive short-term load-bearing capacity of the connection and a dominant mode of failure. Data obtained from the tests are going to be used for further numerical simulations and a parametrical study.

The article deals with sealing of cement-based materials and tensile properties of the sealed joint. Aquapanel cement board was chosen as the base material, which was treated with a primer. Then two sealants were applied, one representative of acrylic and one of polyurethane sealants. After curing, the resulting test specimens were tested according to the valid European standard ČSN EN ISO 8340, which defines the parameters of the test specimen and subsequent test procedures. The evaluation of the test, which took place visually and with a caliper measurement, showed that only polyurethane sealant could be recommended for sealing Aquapanel. This putty, unlike acrylic putty, did not show any defects after the test, so it can be stated as suitable for sealing Aquapanel cement board.

Ukraine has a strong influence on prices and availability of some construction materials. Steel products are the most hit by the war. Rising prices of energies and fuels are influencing the prices of construction materials, too. These unfavourable conditions are seen not only by small investors, but also by municipalities when announcing public tenders. The original price that won the public tender usually rises during the project’s preparation phase and subsequent construction phase. The author of this article analyses the construction materials’ price developments during a period of several years. In the article you can find a pricing of a particular public tender by indicative prices of construction materials and work in different periods.

One of the very essential aspects to ensure adequate durability of composite materials that combine cementitious matrix and wood is the stabilization of the wood structure. Stabilization of the wood structure is particularly important in relation to the moisture effect on the wood-cement composite mechanical properties. Stabilization of the wood matrix is generally carried out by means of suitable types of additives. This paper deals with a detailed analysis of the influence of the wood-cement materials composition in relation to the effect of liquid water. Another essential area of the presented research is the analysing the ability of the modified matrix (by different types of industrial wastes) to fix sugars in the structure of the wood mass, with regard to the possible affecting the hydration process of the cement matrix.

Floor leveling materials have an irreplaceable place in the construction or reconstruction of buildings, especially in the construction of floors where the aim is to reduce the wet process in relation to the speed of completing. Various types of raw materials (expanded clay, aerated concrete, mineralised wood chips, etc.) are used for floor leveling materials. This paper presents research and development of a new type dry leveling floor material based on treated cuttings from cement-bonded particleboard processing. This leveling material is intended for reconstruction and even construction of new floors in buildings. Research and development takes into account the environmental situation, because approximately 5,000 t of cuttings is produced during the formatting of cement-bonded particleboard annualy. The intention of the research and development was to assess the properties and behaviour of the leveling material based on suitably modified cuttings from the production of cement-bonded particleboards. The composition of the cuttings was adjusted in a jaw crusher and subsequently, different variants of the leveling material were analysed in terms of particle size distribution, compressibility, confined compressive strength, water absorption and thermal conductivity coefficient. The properties of the developed material were also compared with the parameters of commonly commercially available leveling materials.

Producers and suppliers of construction materials are dealing with rising prices of raw materials, semi-finished products and lots of different types of products. Insecurity of input raw material supplies for production is on the rise as well. This is due to the concurrence of many unfavourable circumstances.

Plastics are now being directed primarily to healthcare, mainly for the production of protective aids against virus transmission. A large amount of plastics is used for disposable food containers or packaging of goods, which is now more than ever ordered online. The outage of production capacity of global plastics producers in the USA has the biggest impact on plastics prices. Lack of plastics in the US influences significantly the quantity of plastics available on European markets. The subsequent withdrawal of plastics from China and Europe significantly contributes to logistics complications. Insufficient capacity of transport ships, aircraft and rail transport makes delivery times longer.

Reduction or termination of production of some smelters in Europe, rising emission allowance prices, tariff restrictions and a shortage of metals from Asia are contributing to raise metal prices. It is seen on the London Metal Exchange.

Although the long-term bark beetle calamity is not at its end yet, foresters have succeeded in stopping it in many places in the Czech Republic. Logging of bark beetle timber is decreasing and its price increases. The increase is caused not only by the decrease in logging, but also by export of this timber abroad, particularly to China, which is a phenomenon of the last two years.

Pandemic restrictions have impact on availability of workers for materials production, products logistics, sale and on-site assembly. There was a slowdown in construction output in spring and summer 2020. However, a recovery phase has been seen recently and demand for many materials exceeds supply.

The paper describes the changes that has been introduced in the new version of the ČSN 73 0532:2020, all the changes are described in details.

The paper deals with the issue of emerging defects and failures in the construction of industrial floors in relation to concrete technology. The effects of deficiencies in concrete recipes on the occurrence of defects or failures are described, as well as the effects of treatment of the finished structure, laying of concrete and methods of its compaction.

In modern building systems, sound insulation of walls is often made of multi-layer structures. This article deals with the acoustic operation of such structures and discusses the importance of proper implementation. It also warns against limited sound insulation at low frequencies, which is often not given enough attention. Software for calculating sound insulation - INSUL - was used to compare the acoustic behavior of structures and for simulations.

Floor construction is assessed within the thermal field by the heat transfer coefficient and surface temperatures, and in the acoustic field particularly from the point of view of airborne and impact soundproofing. When using ultra-light concrete for the construction of flooring there are unique parameters to consider. Within the contribution, the development occurred of an ultra-light concrete daub that achieved this minimal weight due to an aggregate product based on foam glass. This ultra-light concrete displays a very good ratio of mechanical performance to thermal insulation properties. As a result of these excellent thermal insulation properties, and the design of a concrete daub without joints, the formation of thermal bridges in floor construction can be eliminated.

Together with the professional journal Podlahy, we have prepared a new series, where the authors get acquainted with the basic standard ČSN 74 4505 Podlahy - Common provisions and subsequently with other standards that are important for the floor area, and also respond to comments from opponents and reviewers. The first part of the series describes the most important provisions of ČSN 74 4505 in an annotated form.

The paper deals with the constructions from jet grouting (JG), which is one of the most modern methods of special geotechnical works. JG is the technique of mixing in-situ soil with the energy of high-pressure jet of slurry. The definitions and types of JG are given in the first part: single fluid, double fluid and triple fluid. The second part concerns JG implementation technology and also lists the necessary activities in designing and implementing JG elements and structures. In the third part, examples show the field of use of JG, including deep foundations, for which the example of static load test is given.

In this paper, the authors consider the aspects of routine procedure compared to the expert approach in solving construction defects and failures. For better orientation in the issue the basic terminology of defects and failures sphere is given. Also, the authors describe in details the course of both solutions, contemplate their specific aspects and point out their consequences. An essential part of the article is presentation of the potential benefits of the expert approach, the advantages of the expert approach are emphasized in the conclusion.

The article briefly introduces basic technical terminology, errors and computational algorithms for estimating uncertainty of type A, type B, combined and extended uncertainty of test results and that the test management performs the tasks specified in the standard ČSN EN ISO / IEC 17025.

The paper deals with a case study of building defects inspection of Lužánky Free Time Centre in Brno. It is described the history of the building and the building diagnostics. There were used the survey methods of visual-defectoscopic inspection, semidestructive diagnosis and diagnosis of foundations and foundation soil. The conclusions contain recommendations for immediate and long-term solution of the object's static problems.

This work is focused on the verification of the possibility of using specially modified hazardous waste, solidification product, formed from selected secondary raw materials as solidifying agent and hazardous waste (end-product) as a filler in polymer grout joint material. Totally, two solidification technologies were verified, the first one was wet granulation of raw materials and another one was dry homogenization. It is more advantageous to use dry homogenization technology, which is economically less demanding. The possibility of using a specially modified filler was verified by the appropriate tests, and results showed that the grout joint showed high compressive strength of approximately 50 MPa, flexural strength up to about 20 MPa. Developed material can also be characterized by very good cohesion with the cast basalt.

Fibre-reinforced concrete is increasingly used in structures where its properties can be utilized - especially tensile and residual strength after cracking. For applications in load-bearing fibre-reinforced concrete structures, it is necessary to ensure the uniformity of the steel fibres distribution in its structure. The paper summarizes the current knowledge of fibre-reinforced concrete production and test methods, which can be used to monitor the uniformity of fibres distribution in both fresh and hardened fibre-reinforced concrete.